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I assume the Ellacoya system will handle this

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I assume the Ellacoya system will handle this

http://www.theregister.co.uk/2008/12/01/richard_bennett_utorrent_udp/
Quote
Upset about Bell Canada’s system for allocating bandwidth fairly among internet users, the developers of the uTorrent P2P application have decided to make the UDP protocol the default transport protocol for file transfers. BitTorrent implementations have long used UDP to exchange tracker information – the addresses of the computers where files could be found – but the new release uses it in preference to TCP for the actual transfer of files. The implications of this change are enormous.
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Community Veteran
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Re: I assume the Ellacoya system will handle this

I was just reading that and was about to post a link too, Jim Smiley
The Ellacoyas should be fine, as they do use DPI (Deep Packet Inspection) to identify traffic streams.  The article is a little US-centric where the US are all "Net Neutrality" and "DPI is illegal interception" etc. etc.
In short, barring a brief period where the Ellacoya signatures will need to be updated, I don't think this will have any affect on the Plusnet network.  It might have an affect on some of the peering points and transit providers though.
B.
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Re: I assume the Ellacoya system will handle this

It does seem a little bit of a backward step though doesn't it?
Effectively to move the same quantity of useful data around, there will be an increase in the number of packets being transferred as packets are dropped and lost. At least with TCP packets the various routers along the way could retransmit any missing packets.
I suppose it will also increase the processing overhead of such applications too, as UDP by definition is connectionless, so network cards etc won't request missing packets themselves, rather the application will have to detect missing packets and request retransmission.
/goes to read article.
Community Veteran
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Re: I assume the Ellacoya system will handle this

It's a backwards step in terms of using the appropriate protocol for the task.
However, it will help "leechers" in the US who just want to put their ISPs out of business.  Roll eyes
B.
Plusnet Alumni (retired) _CN_
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Re: I assume the Ellacoya system will handle this

Hi,
A quick read and it looks like uTP (the micro transport protocol) is a protocol on top of UDP built with some reliable transport mechanism in it.  Interestingly it looks to have some flow control feature to prevent saturation of your own connection.  Another thought I'd like to throw in to the discussion, as the UDP header is 12 bytes smaller than the standard TCP header will we see a decrease in BW consumed by BT with these flows of doing thousands of packets, what does that mean to the consumer of these flows too?
David_W
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Re: I assume the Ellacoya system will handle this

What does it mean for time sensitive and highly important things, like games?  If the internet is being flooded with UDP packets does that mean the traffic will be saturated ending up with really important business applications, like Team Fortress 2, having terrible latency?  I guess I'm one of the many who read it and think "the internet is about to fall over".
James
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Re: I assume the Ellacoya system will handle this

From my highly non-technically understand of how things like this work is that it shouldn't impact us.
Whether or not it brings an increase of encrypted bit torrent traffic shouldn't be a massive issue as this will just be prioritised as such.
[me=Jameseh]waits for more clever people to come along to tell James he's wrong Cheesy[/me]
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Re: I assume the Ellacoya system will handle this

I suspect that there may be an impact if a game server is in the US as net neutrality means that they can't use deep packet inspection systems
It could also mean that more ISP's will have to use something similar over here as simple throttling won't work any more
Then again I am not an expert so I also could be totally wrong  Grin
VileReynard
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Re: I assume the Ellacoya system will handle this

Net neutrality doesn't prevent the use of DPI - eg Phorm and it's US imitators use it.
Since Video streaming, audio streaming VOIP and other applications all use UDP,
it seems a bit harsh to attack one mode of utorrent - it can still use TCP.
Personally, I find that most P2P is sent as encrypted TCP - does DPI work on that?

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Re: I assume the Ellacoya system will handle this

Yeah, it still works.
Each IP packet, whether encrypted or not, must contain information pertaining to its destination and contents. (Otherwise how would the devices along the way know where to send it.)
Similar technology is used in SPI (Stateful Packet Inspection), whereby a firewall checks each packet to ensure that its payload matches its headers (ie, its not claiming to be something its not.)
What is being attacked is not uTorrent, its just the delivery medium. UDP packets are simply sent, and no check is made to ensure that the packet arrives at its destination. TCP packets are checked to ensure they arrive in the right order, and any missing ones are requested to be retransmitted.
Many routers cache TCP packets as they pass through, so that if a packet is missed by the downstream recipient, the router can retransmit it, rather than having to request it again from the source.
From this, you can see that any missed packets will have to be requested for retransmission by the ultimate destination - this request must be transmitted all the way back to the original source, and the missed packet must be retransmitted along the whole chain.
Video streaming and VOIP use UDP since the entire stream is time sensitive, and it's generally more important to have the occasional missing frame of video, or stilted word in conversation than it is to delay the whole stream whilst the missing packet is re-requested.
Traffic on the internet can be classified into one or other delivery method, based upon the importance of keeping the delivery in 'real time' with the occasional missing packet, versus allowing the delivery to take slightly longer to ensure that the whole stream arrives complete.
Its relatively easy to look at this and think that UDP would suit torrents, since you want things to download as quickly as possible, and the occasional missing packet is unimportant, since any missing packets will be requested either from the same host, or from another host to complete the file.
The trouble is that most of the traffic on the internet is already torrent/filesharing traffic, and adding in these retransmission requests will undoubtedly increase the traffic burden placed on the infrastructure by this type of traffic.
The net result will depend upon the ISPs and bulk carriers that make up the internet backbone. If all ISPs used similar traffic management methods as PN, the net result would simply be slower torrent downloads, since the overall portion of traffic permitted to traverse the ISPs networks would not increase, therefore the extra signalling requests would take up a portion of this finite resource, resulting in less 'payload' packets being able to be delivered.
If ISPs don't have traffic management that is as intelligent as Plusnet's systems, the net result would be an overall slower performance across all protocols, since the extra traffic would undoubtedly take up some of the spare capacity used by other protocols. [For people using uTorrent where all nodes share a network(s) with similar traffic management traits, actual uTorrent download speed would probably increase in this scenario.]
The reality is that the internet is made up of many diverse networks, and the trend will be for these network owners/operators to implement traffic management similar to Plusnet's system, as otherwise the commercial value of their networks declines as capacity is taken up with traffic that does not pay the bills as well as other types of traffic might. (Think about the commercial value of a transatlantic link, and then consider the implications of taking up an increasing proportion of bandwidth for file-sharing, versus managing the traffic effectively allowing the operator to sell guaranteed chunks of bandwidth to telecomms companies and the like.)
My take on the overall picture is an increasing cost of connectivity, mirrored with a budget alternative of lower performance. Advanced traffic management equipment is not cheap, and the costs have to be found somewhere. Rather than raise prices, which is a bitter commercial pill to swallow, the reality is likely to involve lower performance at the same price point.
The change won't have much effect on performance on PNs network, but you can be assured of an impact in some way once your internet requests leave the haven of the PN network and its immediate peering links.
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Re: I assume the Ellacoya system will handle this

Another article on it http://arstechnica.com/news.ars/post/20081201-utorrents-switch-to-udp-and-why-the-sky-isnt-falling.h...

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thejudge
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Re: I assume the Ellacoya system will handle this

Turns out The Register may have got things base-over-apex:
http://www.slyck.com/story1804_BitTorrent_Switching_to_UDP_Transfers_Nonsense
Plusnet Alumni (retired) _CN_
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Re: I assume the Ellacoya system will handle this

lol, why my reply was to try and engage the other discussion, that this may not all be bad, if only they took time to 'try' to understand a tiny part of what uTP was trying to achieve (only testing and live use will show it does do this though)
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Re: I assume the Ellacoya system will handle this

Trouble is that uTP is effectively trying to do what TCP does anyway, but its putting the burden of doing it onto the processor at each end, as well as the whole network path in between the nodes for the retransmits.
Plusnet Alumni (retired) _CN_
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Re: I assume the Ellacoya system will handle this

I;d say they are trying to slow the packet rate down on detecting an increase in latency etc. before any packet drops are occurring, the Jacobson TCP congestion control only starts when packets have been dropped, at this stage packets need to be retransmitted.  Also as the BitTorrent protocol already does some form of handshaking moving to UDP removes some duplication of functionality already occurring. Some interesting articles have come out of the doom scenario painted by the register, more of the same please register :-)